The development of infrared photodetectors is mainly limited by the choice of available materials and the intricate crystal growth process. Moreover, thermally activated carriers in traditional III–V and II–VI semiconductors enforce low operating temperatures in the infrared photodetectors. Here we demonstrate infrared photodetection enabled by interlayer excitons (ILEs) generated between tungsten and hafnium disulfide, WS₂/HfS₂. The photodetector operates at room temperature and shows an even higher performance at higher temperatures owing to the large exciton binding energy and phonon-assisted optical transition. The unique band alignment in the WS₂/HfS₂ heterostructure allows interlayer bandgap tuning from the mid- to long-wave infrared spectrum. We postulate that the sizeable charge delocalization and ILE accumulation at the interface result in a greatly enhanced oscillator strength of the ILEs and a high responsivity of the photodetector. The sensitivity of ILEs to the thickness of two-dimensional materials and the external field provides an excellent platform to realize robust tunable room temperature infrared photodetectors.

红外光电探测器的发展主要受限于可用材料的选择和复杂的晶体生长过程。此外，传统 III-V 和 II-VI 半导体中的热激活载流子在红外光电探测器中强制要求较低的工作温度。在这里，我们展示了由钨和二硫化铪 WS ₂ /HfS ₂之间产生的层间激子 (ILE) 实现的红外光电探测。由于大的激子结合能和声子辅助的光学跃迁，光电探测器在室温下工作，并在更高的温度下表现出更高的性能。_{WS 2} /HfS ₂中独特的波段对齐异质结构允许从中波到长波红外光谱进行层间带隙调谐。我们假设界面处相当大的电荷离域和 ILE 积累导致 ILE 的振荡器强度和光电探测器的高响应度大大增强。ILE 对二维材料厚度和外场的敏感性为实现稳健的可调谐室温红外光电探测器提供了一个极好的平台。